The present invention is in the field of surveillance, and in particular relates to an undetected method viewing through tinted windows.
U.S. Pat. No. 6,150,930 discloses a video system mounted on the front of an automobile to improve visibility at night or in low visibility conditions, e.g., fog, smoke or snow. An illuminator fixedly mounted on the front of the automobile lights up the road ahead. A video camera and video system combines the visible and near infrared reflections onto a video monitor to improve visibility. A similar but operator controlled and portable system is used in the present invention to provide a method of covertly inspecting the interior of structures or vehicles having tinted windows.
Tinted windows are commonly used on automobiles and in buildings to reduce the sun""s glare. They do not significantly reducing the visibility of a person looking out, particularly during daylight conditions. In low light or nighttime conditions, however, tinted windows prevent a person on the outside from seeing into an automobile or building when the interior is unlit. This can present a serious problem for law enforcement personnel, who for example, stop an automobile in the course of their duties. The tinted windows obscure the activities of the car""s occupants leaving the officer in a potentially vulnerable situation.
Consequently, there is a law enforcement need for an undetectable method of viewing the interior of an automobile or building with tinted windows in low light conditions.
In a preferred embodiment, the interior of structures having tinted windows is illuminated by a broadband near infrared (NIR) light source and the illuminated scene is viewed using a standard video camera and monitor.
Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawing, illustrating by way of example the principles of the invention.